A phosphonate chiral diastereomeric oxime ester compound, and a preparation method and application thereof

Abstract

This invention relates to a phosphate-containing chiral diastereomeric oxime ester compound, its preparation method, and its applications, belonging to the field of organic synthesis technology. This invention introduces a chiral center at a specific location in the molecular structure of the oxime ester compound to form a mixture of diastereomeric stereoisomers. The introduction of the chiral center interferes with intermolecular chiral recognition, thereby effectively suppressing the π-π stacking effect and crystal growth between the aromatic ring cores. Furthermore, the introduction of the phosphate ester structure into the product effectively improves its solubility in propylene glycol methyl ether acetate or cyclohexanone solvents. The photocurable ink prepared using the diastereomeric oxime ester compound of this invention exhibits excellent storage stability and better photosensitivity.

Description

Technical Field

[0001] This invention relates to a chiral diastereomeric oxime ester compound of the phosphate class, its preparation method and application, belonging to the field of organic synthesis technology. Background Technology

[0002] Oxime esters are known highly efficient photoinitiators for radiation-induced polymerization of unsaturated olefinic compounds. Their broad light absorption characteristics, extending from short-wave ultraviolet light to long-wavelength light (350-420 nm), enable them to exhibit excellent photopolymerization initiation capabilities under both traditional high-pressure mercury lamps and energy-efficient LED light sources. They have wide applications in photocurable PCB inks, specialty coatings, printing and packaging inks, adhesives, composite materials, optical fibers, and TFT-LCD liquid crystal displays. Commercially available products include BASF's Irgacure OXE-01 and OXE-02. Related patents include CN101014569, WO2009147033, CN101528694, CN102250115, and WO2008078678.

[0003] With the advancement of photolithography technology, the performance requirements for oxime ester products are becoming increasingly stringent, particularly in terms of two key indicators: solubility and i / g / h line wavelength photosensitivity. Since industrial applications such as flat panel display manufacturing typically use solvent systems with specific technical parameters, primarily propylene glycol methyl ether acetate (PGMEA) or cyclohexanone, to ensure the low-temperature storage stability of ink formulations, oxime ester photoinitiator compounds must exhibit excellent solubility in these specific solvent systems (the usual standard is a solubility of 8% by weight or higher at room temperature).

[0004] Oxime esters with carbazole aromatic heterocycles as their backbone possess outstanding i / g / h linear photosensitivity. A prominent issue in application testing is their poor solubility in propylene glycol methyl ether acetate or cyclohexanone solvent systems. Even after initial heating and / or shear stirring to promote dissolution, precipitation gradually occurs during subsequent low-temperature storage (3–6 months). Molecular structural analysis reveals that carbazole aromatic heterocycles are typical planar π-electron conjugation systems, making them highly susceptible to π-π stacking crystallization. This induces intermolecular recognition and subsequent accumulation of monomer molecules during low-temperature storage, leading to precipitation.

[0005] Therefore, there is an urgent need to develop an oxime ester compound with a carbazole aromatic heterocycle backbone that has good solubility in propylene glycol methyl ether acetate or cyclohexanone solvent systems. Summary of the Invention

[0006] The purpose of this invention is to provide a chiral diastereomeric oxime ester compound of phosphate ester, its preparation method and application, so as to solve the problems of poor solubility of current oxime ester compounds in propylene glycol methyl ether acetate or cyclohexanone solvent systems and poor photosensitivity when used as photoinitiators.

[0007] This invention provides a chiral diastereomeric oxime ester compound of the phosphate ester class, having the structure shown in Formula I: In formula I, ★ Represents the chiral center; R1 is a straight-chain or branched C1-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; R2 is a straight-chain or branched C3-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; and R2 contains at least one chiral center, each chiral center being 2-10 chemical bond distances from the carbazole aromatic ring core. R3 is -NO2, -CN, or R4 is a C6-C24 aryl group containing 0-6 non-hydrogen substituents or a C6-C24 heteroaryl group containing 0-6 non-hydrogen substituents.

[0008] Preferably, R1 is -CH3, -Ph, -CH3CH2-, -CF3, -CF3CF2-, -C4F9-, -C8F 17 -

[0009] Preferably, each chiral center is 2 to 6 chemical bonds away from the carbazole aromatic ring core.

[0010] Preferably, R1 is a C1-C3 alkyl group and R2 is a C1-C8 alkyl group.

[0011] Preferably, R1 is -CH3, and R2 is R3 is -NO2.

[0012] It is understood that non-hydrogen substituents refer to atoms or groups other than hydrogen atoms, including but not limited to oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, halogen atoms, alkyl groups, aryl groups, and heteroaryl groups.

[0013] This invention provides a method for preparing the chiral diastereomeric oxime ester compound of the phosphate ester class as described above, comprising the following steps: (1) Carbazole and bromochloroalkanes were subjected to a substitution reaction to obtain halocarbazole compounds; (2) A halogenated carbazole compound and a phosphite compound were subjected to a substitution reaction to obtain a phosphonate-substituted carbazole compound; (3) Nitrate the phosphonate-substituted carbazole compound to obtain the nitro-substituted carbazole compound; (4) Nitro-substituted carbazole compounds and acyl chloride compounds are subjected to Friedel-Crafts acylation reaction to obtain ketone-substituted carbazole compounds; (5) The ketone group in the ketone-substituted carbazole compound is condensed with hydroxylamine hydrochloride to obtain a carbazole compound substituted with hydroxamic acid; (6) Esterification reaction of carbazole-substituted hydroxamic acid and acyl chloride compounds yields chiral diastereomer oxime ester compounds of phosphate esters.

[0014] Preferably, in step (1), the molar ratio of carbazole to bromochloroalkanes is 0.4:2.4~2.6, and the temperature for the substitution reaction of carbazole and bromochloroalkanes is 53~58℃; in step (2), the molar ratio of halocarbazole compound to phosphite compound is 0.4:0.7~0.8, and the temperature for the substitution reaction of halocarbazole compound and phosphite compound is 160~170℃.

[0015] Preferably, in step (3), the nitration reaction of the phosphonate-substituted carbazole compound is carried out by mixing the phosphonate-substituted carbazole compound and dilute nitric acid at 3~7°C; in step (4), the molar ratio of the nitro-substituted carbazole compound and the acyl chloride compound is 1:1~2, and the Friedel-Crafts acylation reaction of the nitro-substituted carbazole compound and the acyl chloride compound is carried out at 5~10°C.

[0016] Preferably, in step (5), the molar ratio of the ketone-substituted carbazole compound and hydroxylamine hydrochloride is 0.8~0.9:1~1.1, and the temperature at which the ketone group in the ketone-substituted carbazole compound and hydroxylamine hydrochloride undergo condensation reaction is 68~70℃.

[0017] The application of a phosphate ester chiral diastereomer oxime compound as described above as a photoinitiator.

[0018] The beneficial effects of this invention are as follows: This invention introduces a monophosphate ester and a chiral center at a specific position in the molecular structure of the oxime ester compound to form a diastereomeric stereoisomer mixture. The introduction of the chiral center interferes with its intermolecular chiral recognition, thereby effectively suppressing the π-π stacking effect and crystal growth between its aromatic ring cores, and effectively improving its solubility in propylene glycol methyl ether acetate or cyclohexanone solvents; the photocurable ink prepared using the diastereomeric oxime ester compound of this invention has excellent storage stability. Attached Figure Description

[0019] Figure 1 The above is the 1H NMR spectrum of the phosphate ester chiral diastereomer oxime compound prepared in Example 1 of this invention; Figure 2 This is the mass spectrum of the chiral diastereomeric oxime ester compound of the phosphate ester prepared in Example 1 of the present invention. Detailed Implementation

[0020] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the present invention.

[0021] The applicant of this invention unexpectedly discovered in experiments that a class of phosphate ester chiral diastereomer oxime compounds described by general formula I, by introducing a phosphate ester and a chiral center at a specific location in the molecular structure to form a mixture of diastereomer stereoisomers, interferes with intermolecular chiral recognition, thereby effectively suppressing the π-π stacking effect and crystal growth between the aromatic ring cores, and thus effectively improving their solubility. Simultaneously, introducing a phosphate ester structure into the compound structure can further effectively improve its solubility in propylene glycol methyl ether acetate or cyclohexanone solvents. The compounds shown in Formula I exhibit superior (over 45%) PGMEA or cyclohexanone solubility, as well as excellent i / g / h line wavelength exposure photosensitivity.

[0022] In formula I, ★ Represents the chiral center; R1 is a straight-chain or branched C1-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; R2 is a straight-chain or branched C3-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; and R2 contains at least one chiral center, each chiral center being 2-10 chemical bond distances from the carbazole aromatic ring core. R3 is -NO2, -CN, or R4 is a C6-C24 aryl group containing 0-6 non-hydrogen substituents or a C6-C24 heteroaryl group containing 0-6 non-hydrogen substituents.

[0023] Hereafter, R1 is -CH3 and R2 is... Taking the compound corresponding to R3 being -NO2 as an example, the preparation method and performance testing are explained. Example

[0024] The method for preparing the chiral diastereomeric oxime ester compound of the phosphate ester in this embodiment includes the following steps: (1) Add 128g (3.2mol) of sodium hydroxide, 260g of water, and 66.8g (0.4mol) of carbazole to a 1000mL four-necked flask. Stir at 40~50℃ for 40min. Then add 380g (2.41mol) of 1-bromo-3-chloropropane. The reaction system automatically heats up to 55℃. Then maintain the temperature of the reaction system at 53~58℃ and stir for 2h. Take a sample for analysis. If the raw material content is less than 1%, it is qualified. Separate the alkaline water layer and wash the organic layer once with 200g of water at a temperature of 20~ At 25℃, add 200g of water, adjust the pH to 2-5 with hydrochloric acid, let stand and separate the layers, wash once with 200g of water, let stand and separate the layers again, first desolvate the organic layer with water pump under reduced pressure to dryness (the temperature of reduced pressure distillation is 125-135℃, and the pressure is 0.01MPa), then desolvate with oil pump under reduced pressure (the temperature of reduced pressure distillation is 125-135℃, and the pressure is 200Pa-400Pa), to obtain a concentrate. The main component of the concentrate is 1-bromo-3-chloropropane, totaling 276g. The concentrate is named WL45-1 and is directly used for the next synthesis.

[0025] (2) In a 500 mL reaction flask (the reaction flask is equipped with a distillation apparatus, using a Claisen distillation head), add WL45-1 (0.4 mol) synthesized in step (1), 120 g (0.723 mol) of triethyl phosphite, and 0.9 g of potassium iodide. Purge with nitrogen gas and turn on the heating. When the temperature reaches 140 °C, chloroethane and triethyl phosphite will distill off. The temperature will be raised from room temperature to 160 °C for 1 hour. The reaction system will be stirred at 160~170 °C. After 6 hours, add 0.4g of potassium iodide and continue stirring for another 3 hours. After the reaction is complete, cool to below 60℃ and distill off 43g of chloroethane (containing triethyl phosphite). First, use a water pump to distill off most of the triethyl phosphite, then use an oil pump to perform vacuum distillation on the material at a temperature of 150℃ and a pressure of 200Pa~400Pa, distilling off 107.6g of triethyl phosphite. The concentrate, named WL-45-2, is used directly in the next synthesis step.

[0026] (3) In a 1000mL four-necked flask, add 0.4mol of WL-45-2 synthesized in step (2) and 700g of dichloroethane, stir and cool to 5℃, keep the temperature of the material in the four-necked flask at 3~7℃, add 107.4g of 58% dilute nitric acid dropwise to the four-necked flask, the total dropwise addition time of the dilute nitric acid is 3.5~4.0h. After the addition is completed, stir for 30min and take a sample for analysis. After passing the test, immediately add 200g of water for dilution, stir for 15min, let stand for 30min, separate the layers, wash the organic layer with water twice, each time with 200g of water, recover the dichloroethane, add 150g of toluene, dissolve at 70~80℃, cool to 10~15℃ for crystallization, filter, dry to obtain 118.4g of crude product, the yield is 75.9%. The crude product was then recrystallized once with 120g of toluene, dissolved by heating to 70-80℃, and crystallized by cooling to 15℃. After filtration and drying, 104.4g of the primary crystal was obtained, with a yield of 66.9%. The secondary crystal was named WL-45-3 and used in the next synthesis.

[0027] (4) Add WL-45-3 (391.2 g by mass), aluminum trichloride 135.5 g (1.01 mol), and dichloroethane 1300 g synthesized in step (3) to a 3000 mL four-necked flask. Stir to dissolve (exothermic reaction occurs), then cool to 5-10 °C. Begin adding isonononyl chloride (1-1.2 mol by molar amount) dropwise over 3.5-4 h at a temperature of 5-10 °C. After the addition is complete, maintain the temperature of the material in the four-necked flask at 5-10 °C. Stir the reaction for 0.5 h, then take a sample for HPLC analysis (raw material content less than 1%). If the sample is qualified, proceed with the reaction. Hydrolysis was carried out by slowly adding a mixture containing 2500 mL of water and 135 g of concentrated hydrochloric acid to the reaction system at a temperature of 8-15 °C for 1-2 h. After the addition was complete, the temperature was maintained at 10-15 °C and stirring was continued for 2 h. The mixture was allowed to stand and separate into layers. The organic phase was then washed three times with water to pH 6-7, using 1000 g of water each time. The solvent was recovered by vacuum distillation, yielding 518 g of residue. 1600 g of methanol was added, and the mixture was refluxed for 0.5 h. After cooling to 10-15 °C, the mixture was crystallized and filtered to obtain 366.2 g of a yellow product (named WL-45-4) with a purity of 98% and a yield of 84.5%.

[0028] (5) Add WL-45-4 (361.2g) synthesized in step (4), 73.8g (1.062mol) of hydroxylamine hydrochloride, and 1700g of methanol to a 2000mL four-piece flask. Heat to 68℃ and reflux. Slowly add sodium carbonate aqueous solution (sodium carbonate aqueous solution is prepared by 56.3g of sodium carbonate and 300g of water) under reflux. Control the reaction temperature to 68~70℃ and the sodium carbonate aqueous solution to be added for 2~2.5h. After the addition is complete, reflux for 30min and take a sample for HPLC analysis. If it is qualified (raw material is less than 1%), stop the reaction, filter, wash the filter cake three times with water, and then wash with methanol under reflux for 1h. Cool to 20℃, filter out the product, and dry to obtain a yellow powder product (named WL-45-5) 348.9g, melting point 196.6~197.8℃, purity 95.8%, and yield 94.3%.

[0029] (6) Add 545.6 g of PI-4-5 synthesized in step (5) and 2400 g of dichloroethane to a 3000 mL reaction flask. Add a drying tube, stir and cool to 0-5 °C. Then add a dichloroethane solution of acetyl chloride dropwise to the reaction flask, controlling the reaction temperature at 0-5 °C and the dropwise addition time at 30 min. A total of 95.4 g (1.215 mol) of acetyl chloride, 123 g (1.218 mol) of triethylamine, and 335 g of dichloroethane are used. After all the materials are added, neutralize the materials to pH 5-6, and then keep the reaction system temperature at 0-5 °C and continue stirring for 1 h. Take a sample. After HPLC analysis (main purity up to 96%), and upon passing the test, 20 g of water was slowly added dropwise to the reaction mixture for hydrolysis. Then, 600 g of water was added for washing at 20-25°C. The mixture was allowed to stand and separate into layers. The organic phase was then washed with water again. The final organic phase was concentrated to dryness under reduced pressure in a water bath at 50-55°C. It was then dissolved in 1250 g of ethyl acetate, cooled to 10°C, stirred for 4 hours, crystallized, and filtered. The resulting filter cake was dried to obtain 330 g of a chiral diastereomeric oxime ester compound (named compound WL-45), with a purity of 97% and a yield of 75%. The melting point of compound WL-45 is 78-80°C.

[0030] The chemical reactions involved in the preparation method of the phosphate ester chiral diastereomeric oxime ester compound in this embodiment are as follows:

[0031] .

[0032] As an example comparison, we prepared achiral but full-carbon equivalent analogs of compound WL-45, including a phosphate ester-containing analog A, a chiral full-carbon analog B containing both R2 and R3 chiral side chains, a branched equivalent analog C containing a phosphate ester with R2 being achiral and full-carbon, and a short-chain equivalent analog D containing a phosphate ester with R2 being achiral and full-carbon. Compared with compound WL-45, structural analogs A and C with the same number of carbon atoms, due to the presence of phosphate esters and the absence of phosphate esters in B, or the presence of phosphate esters but diastereomers in D, effectively suppress the interference of intermolecular chiral recognition. This leads to a tendency for π-π stacking between the aromatic ring cores, resulting in continuous lattice growth, a sharp decrease in solubility, and eventual precipitation, as well as reduced photosensitivity. The chemical structures of compounds A, B, C, and D are as follows:

[0033]

[0034] .

[0035] The specific preparation methods for compounds A, B, C, and D are as follows: Comparative Example 1 The preparation method of the oxime ester compound in this comparative example differs from the preparation method of the phosphate ester chiral diastereomeric oxime ester compound in Example 1 only in that isononanoyl chloride in step (4) is replaced with nonanoyl chloride. The oxime ester compound obtained is named compound A. The oxime ester compound is a pale yellow solid powder with the following chemical structure: .

[0036] Comparative Example 2 The preparation method of the oxime ester compound in this comparative example differs from the preparation method of the phosphate ester chiral diastereomeric oxime ester compound in Example 1 only in that 1-bromo-3-chloropropane in step (1) is replaced with bromoisooctane. The oxime ester compound obtained is named compound B. The oxime ester compound is a yellow solid powder with the following chemical structure: .

[0037] Comparative Example 3 The preparation method of the oxime ester compound in this comparative example differs from the preparation method of the phosphate ester chiral diastereomeric oxime ester compound in Example 1 only in that isononanoyl chloride in step (4) is replaced with 7-methyl-n-octanoyl chloride. The resulting oxime ester compound is named compound C. The oxime ester compound is a yellow solid powder with the following chemical structure: .

[0038] Comparative Example 4 The preparation method of the oxime ester compound in this comparative example differs from the preparation method of the phosphate ester chiral diastereomeric oxime ester compound in Example 1 only in that isononanoyl chloride in step (4) is replaced with acetyl chloride. The oxime ester compound obtained is named compound D. The oxime ester compound is a yellow solid powder with the following chemical structure: .

[0039] Experimental Example 1 This experiment is a solubility test. The experimental method is as follows: At room temperature, using PGMEA as the standard solvent, the solubility of the oxime ester compounds prepared in Example 1 and Comparative Examples 1-4, as well as the conventional photoinitiator OXE-02, was measured under the same conditions. The results are as follows: The solubility of the phosphate ester diastereomer oxime ester compounds prepared in Example 1 is greater than 50%; the solubility of compound A is less than 17%; the solubility of compound B is less than 8%; the solubility of compound C is less than 19%; the solubility of compound D is less than 12%; and the solubility of photoinitiator OXE-02 is less than 5%. These data confirm that the phosphate ester-containing diastereomer oxime ester compounds prepared in Example 1 with chiral centers all have excellent solubility in PGMEA solvent, especially when containing phosphate esters, the solubility increases significantly.

[0040] Experiment Example 2 This experiment is a storage stability test. The experimental method is as follows: Using the black matrix (BM) ink system for color filter (CF) manufacturing provided by Shenzhen Huaxing Optoelectronics Technology Co., Ltd. as the standard formulation (PGMEA is the diluent solvent and does not contain photoinitiators), the oxime ester compounds prepared in Example 1 and Comparative Examples 1-4 were added as photoinitiators at a dosage of 7% under high-speed stirring. The compounded inks were stored at approximately 4°C for 105 days. Microscopic observation of smears showed that inks containing oxime ester compounds A, B, C, and D all exhibited particle precipitation, while the ink containing the phosphate ester diastereomer oxime ester compound prepared in Example 1 did not exhibit particle precipitation. This demonstrates that the inks prepared using the diastereomer oxime ester compounds of this invention have excellent storage stability.

Claims

1. A chiral diastereomeric oxime ester compound of the phosphate ester class, characterized in that, It has the structure shown in Equation I: ， In formula I, ★ Represents the chiral center; R1 is a straight-chain or branched C1-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; R2 is a straight-chain or branched C3-C24 alkyl group containing 0-12 non-hydrogen substituents, or a C6-C24 aryl group containing 0-6 non-hydrogen substituents; and R2 contains at least one chiral center, each chiral center being 2-10 chemical bond distances from the carbazole aromatic ring core. R3 is -NO2, -CN, or R4 is a C6-C24 aryl group containing 0-6 non-hydrogen substituents or a C6-C24 heteroaryl group containing 0-6 non-hydrogen substituents.

2. The phosphate ester chiral diastereomeric oxime compound as described in claim 1, characterized in that, R1 is preferably -CH3, -Ph, -CH3CH2-, -CF3, -CF3CF2-, -C4F9-, -C8F 17 - 3. The phosphate ester chiral diastereomeric oxime compound as described in claim 1, characterized in that, Each chiral center is 2 to 6 chemical bonds away from the carbazole aromatic ring core.

4. The phosphate ester chiral diastereomeric oxime compound as described in claim 1, characterized in that, R1 is a C1~C3 alkyl group, and R2 is a C1~C8 alkyl group.

5. The phosphate ester chiral diastereomeric oxime compound as described in claim 4, characterized in that, R1 is -CH3, R2 is R3 is -NO2.

6. A method for preparing a chiral diastereomeric oxime ester compound of phosphate esters as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Carbazole and bromochloroalkanes were subjected to a substitution reaction to obtain halocarbazole compounds; (2) The halocarbazole compound and the phosphite compound were subjected to a substitution reaction to obtain the phosphonate-substituted carbazole compound; (3) Nitrate the phosphonate-substituted carbazole compound to obtain the nitro-substituted carbazole compound; (4) The nitro-substituted carbazole compound and the acyl chloride compound were subjected to Friedel-Crafts acylation reaction to obtain the ketone-substituted carbazole compound; (5) The ketone group in the ketone-substituted carbazole compound is condensed with hydroxylamine hydrochloride to obtain a carbazole compound substituted with hydroxamic acid; (6) Esterification reaction of carbazole-substituted hydroxamic acid and acyl chloride compounds yields chiral diastereomer oxime ester compounds of phosphate esters.

7. The method for preparing the phosphate ester chiral diastereomeric oxime compound as described in claim 6, characterized in that, In step (1), the molar ratio of carbazole to bromochloroalkanes is 0.4:2.4~2.6, and the temperature for the substitution reaction of carbazole and bromochloroalkanes is 53~58℃; in step (2), the molar ratio of halocarbazole compound to phosphite compound is 0.4:0.7~0.8, and the temperature for the substitution reaction of halocarbazole compound and phosphite compound is 160~170℃.

8. The method for preparing the chiral diastereomeric oxime ester compound of phosphate esters as described in claim 6, characterized in that, In step (3), the nitration reaction of the phosphonate-substituted carbazole compound is carried out by mixing the phosphonate-substituted carbazole compound and dilute nitric acid at 3~7℃; in step (4), the molar ratio of the nitro-substituted carbazole compound and the acyl chloride compound is 1:1~2, and the Friedel-Crafts acylation reaction of the nitro-substituted carbazole compound and the acyl chloride compound is carried out at 5~10℃.

9. The method for preparing the chiral diastereomeric oxime ester compound of phosphate esters as described in claim 6, characterized in that, In step (5), the molar ratio of the ketone-substituted carbazole compound and hydroxylamine hydrochloride is 0.8~0.9:1~1.1, and the temperature at which the ketone group in the ketone-substituted carbazole compound and hydroxylamine hydrochloride undergo condensation reaction is 68~70℃.

10. The use of a phosphate ester chiral diastereomeric oxime compound as described in any one of claims 1-5 as a photoinitiator.

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